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Alternator problem?
Posted: Fri Dec 08, 2006 10:21 am
by zhenjie
I have a stalling problem which I think could be due to a dodgy Alternator/Battery or bad tune.
When i rev the car it off the throttle the revs drop very suddenly and will dip to below 500rpm and in some cases would stall the car.
I've done a test where by I place my left foot on the brake pedal and then I rev the car. The brake pedal goes hard, then soft, then hard,etc in relation to the throttle. So I assume theres something wrong with the power assist that could be linked to a dodgy alternator?
Posted: Fri Dec 08, 2006 12:11 pm
by bruce
1. Brakes are not power assisted (no electrical assistance at all). They are vacuum assisted.
2. Almost sounds like the Spark plug leads again?
Posted: Fri Dec 08, 2006 2:00 pm
by Garry
Try resetting your base idle speed.
Re:
Posted: Fri Dec 08, 2006 3:14 pm
by zhenjie
bruce wrote:1. Brakes are not power assisted (no electrical assistance at all). They are vacuum assisted.
2. Almost sounds like the Spark plug leads again?
*hits head*. I'll check the spark plug leads tonight I guess.
I have tried fiddling with the base idle speed because previously it was idling very roughly and at around 500rpm. It still drops below the normal 800rpm when its coming down from quick high revving.
Re:
Posted: Fri Dec 08, 2006 4:50 pm
by JBT
zhenjie wrote:I have tried fiddling with the base idle speed because previously it was idling very roughly and at around 500rpm. It still drops below the normal 800rpm when its coming down from quick high revving.
Are you sure you used the correct procedure to adjust it?
Re:
Posted: Fri Dec 08, 2006 4:52 pm
by Juffa
zhenjie wrote:.
I have tried fiddling with the base idle speed because previously it was idling very roughly and at around 500rpm. It still drops below the normal 800rpm when its coming down from quick high revving.
This is a known problem with MX-5s. Have a search on the big forum as there are heaps of posts covering the fix for this issue.
Just had a look in the Miata net garage and found this...
http://www.miata.net/garage/ignition.html#idleJ
Re:
Posted: Fri Dec 08, 2006 6:24 pm
by Juffa
Steve 818 wrote:Zhen has an aftermarket ECU fitted on his car and his problem could very easily be a tuning issue with the ECU. My ECU did that for a while too until I adjusted the fuel and ignition zones at idle rpm and kPa.
Ah yes, you are correct. Forget what I said ealier. If it is like my Fm/Link ECU the normal tuning instructions don't fully apply.
J